Staphylococci and streptococci are usually often regarded as a group of gram positive bacteria, which develops purulent matter (pus) at infections, so called pathogenic cocci. This group does not only contain the classical Staphylococcus aureus and Streptococcus pyogenes (group A streptococcus), but also other staphylococci and streptococci, such as Staphylococcus epidermis, Staphylococcus haemolyticus, Staphylococcus hyicus, streptococci of Groups B, C, G, and H, viridans streptococci, etc. Even gram negative bacteria such as Escherichia coli can cause such infections.
These pathogenic bacterial strains causes different infections in man and in animals all the way from small selfhealing skin infections, to serious sepsis (blood infection). At the infection of animals by these strains the animals are not only suffering, but also great economical damages are caused to the owners of the animals due to production cut-off. Mastitis in milking cows is such an economically damaging infection.
In man such bacterial strains cause i.a. heart valve infections, but also other infections as the commonly known "hospital illness", i.e., most often an infection of an open wound, which shows difficulties in healing, can produce large amounts of pus, and can cause reoperation. Particularly, the heart valve infections threatens risk groups already exposed within the hospital care.
The term wound used means that normally covering epithelial cellular layer, and other surface structures have been damaged by mechanical, chemical, or other influence. The term wound can hereby be divided into two main groups, viz: surface wounds, and deep wounds. The term surface wound means a trauma on the surface of the body or a surface in direct connection to the cavities of the body, i.e., the gastro-intestinal duct, mouth cavity, urethra, milk ducts, etc. The term deep wounds means trauma in the inner of a body caused by violent outer assault or by surgical incisions in different tissues.
When a wound is caused, fibronectin, fibrinogen, collagen, and/or laminin are exposed in the wound tissue. These proteins form together with so called proteoglucans a net work structure in different reinforcement tissues, and is the structure onto which connective tissue (fibroblasts) and epithelial cells grow at a natural wound healing.
The natural wound healing can, however, be prevented by pathogenic bacteria colonizing therein, primarily by pyogenic cocci, and secondly by other pathogenic strains, such as E. coli and other gram negative rod shaped bacteria.
Examples of such a colonizing of damaged tissue are:
i) colonizing of wounds in skin and connective tissue, which wounds have been caused by a mechanical violence, chemical damage, and/or thermal damage; PA0 ii) colonizing of wounds on mucuous membranes, such as in the mouth cavity, or in the mammalian glands, urethra, or vagina; PA0 iii) colonizing on connective tissue proteins, which have been exposed by a minimal tissue damage (microlesion) in connection with epithelial and endothelial (mastitis, heart valve infection).